The peaks of derivatives of absorption were labeled as 1stpeak, 2nd-peak, 3rd-peak and 4th-peak from the side of low
photon energy toward the side of high photon energy. Table
3 shows the photon energy corresponding to the peaks of
derivatives of absorption of standard samples obtained by
Figure 5 and Figure 6.
Figure 7 shows XANES spectra for the deposits on the
insulating papers after heating tests in oil A (DBPC free). It
was found that the deposits were mainly Cu2S, because the
observed peaks of derivatives of absorption were
corresponded to the photon energy of 8979eV and 8982eV,
and were not corresponded to the photon energy of 8992eV
regardless of the oxygen concentration in atmospheres.
Also, the observed peaks of derivatives of absorption
increased with the oxygen concentration in atmospheres. It
indicates Cu2S deposition on the insulating paper is
accelerated with the existence of oxygen